1. Field of the Invention
The present invention relates to a motor having improved reliability, and more particularly to an axial movement restriction mechanism and a circular movement restriction mechanism of a shaft and a rotor core affixed to the shaft.
2. Description of the Related Art
A motor used in a vehicle such as a passenger car, or the like, is expected to operate reliably in various environments. In particular, the motor is expected to withstand external vibrations and/or shocks applied to the motor. In order to achieve the expected durability and reliability, the motor includes multiple layers of security features. For example, a plurality of elements forming a rotor of the motor rotating centered about the central axis are configured so as not to move excessively in the axial direction and the circumferential direction.
Hereafter, a configuration of a conventional rotor of a motor will be described with reference to FIG. 10. FIG. 10 is a schematic cross-sectional view of the conventional rotor.
According to FIG. 10, a rotor 6 includes a shaft 61 arranged concentrically with a predetermined central axis J1, a rotor core 62 having an inner circumferential surface which is affixed to an outer circumferential surface of the shaft 61 by adhesive, press fitting, or the like, and a rotor magnet 63 affixed to an outer circumferential surface of the rotor core 62.
Due to such configuration in which the outer circumferential surface of the shaft 61 and the inner circumferential surface of the rotor core 62 are secured to one another via adhesive or press fitting, when an external impact is applied thereto in an axial direction, the shaft 61 and the rotor core 62 may be displaced with respect to one another. When an external diameter of the shaft 61 is small, a contact surface between the outer circumferential surface of the shaft 61 and the inner circumferential surface of the rotor core 62 is limited, and consequently, reliability of the connection between the shaft 61 and the rotor core 62 is compromised.